This invention relates to the field of moveable and portable acoustic shells, as well as acoustic sound control. “Acoustic shells (or sound shells) are physical structures designed to capture sound produced in a performance area of a performance arts venue and to project the sound into an audience area of the venue,” U.S. Pat. No. 7,815,011 (Holzman, et al.). “In addition to outward sound projection, an acoustical shell enables the individual performers to hear themselves and those around them so that they can make any necessary adjustments for intonation purposes without having to force their volume output in order to be heard,” U.S. Pat. No. 5,525,766 (Atcheson et al.). Atcheson also teaches that “For many indoor performance settings, such as, for example, concert halls, auditorium or gymnasiums, the acoustics are less than ideal. In such indoor performance settings, an acoustical shell can help overcome the acoustical shortcomings of the performance area by keeping the sound from being lost to the sound-absorbing regions above the performance area, thereby allowing the performers to hear themselves better so that they can project a better blended sound to the audience.”
In the prior art, the acoustic shell encloses portions of the performance area with a back wall, side walls, and a canopy (above the performance area). Such an acoustic shell acts in some ways like a megaphone or bull horn, with sound produced at the narrow end of the megaphone (the rear of the acoustic shell) and emitted towards the audience at the wider of the megaphone (the wider front of the shell). The most efficacious acoustic shells enclose all sides and top of the performance area, but portability concerns have often required some compromises in coverage. The canopy may extend beyond the performance area as well, U.S. Patent Application Publication No. 2011/0024225 (Stephenson, et al.).
In the prior art, portable acoustic shells have often consisted of individual, free-standing panels which can be set up individually behind musicians, or placed side-by-side in a line or semi-circle to form a shell. See, for example, U.S. Pat. No. 3,180,446 (Wenger); U.S. Pat. No. 6,085,861 (Jines); U.S. Pat. No. 5,651,405 (Boeddeker, et al.); U.S. Pat. No. 4,278,145 (Eade); U.S. Pat. No. 5,069,011 (Jenne); U.S. Pat. No. 7,918,312 (Carlson); and U.S. Pat. No. 8,091,605 (Melhart).
Portable acoustic shells have been composed of various materials, and have been structurally supported in various ways. The reflective properties of flexible sheet-like materials and fabrics have been used to construct partial shells (see Carlson) or entire band-shells (see bandshell by Anchor that looks like half of a tent: http://anchorinc.com/products/tents-fabric-structures/tension-tents/bandshells.
In all of the prior art, the audience area is conceived of as everything within line of sight of the performance area (essentially, the entire area in front of the musicians). Prior art acoustic shells may well double the sound volume everywhere in the audience area (see decibel mappings in Stephenson.)
Nonetheless, there are many events at which music is played, but many of the attendees have not come for the music and do not care to listen to the music. At the same time, it is desirable that all attendees can see each other to promote a feeling of inclusiveness. Examples include wedding receptions and college reunions, where some attendees want to dance, and others want to talk to each other—but nonetheless, all want to feel part of the same event. For this reason, they want to see each other and not be partitioned into separate spaces which would allow conventional acoustic partitions to acoustically isolate the separate spaces. Consequently, there is a need for a portable acoustic treatment which (a) provides aural feedback to musicians in the performance area, (b) projects sound onto only a portion of the total area within the line of sight of the musicians, and (c) limits the sound which reaches other portions of the venue.
This need is particularly acute in the case where such events are held under temporary tent-like structures (i.e., temporary building structures).
Large tents are used as temporary cover for out-of-doors social events such as college reunions and wedding receptions. These tents provide efficient cost-effective shelter from inclement weather (or threat of same), and often for large crowds. However, they have notoriously bad acoustics when one large portion of the people under the tent primarily want to talk to each other with little or no background music and another large portion want to primarily dance to music. (In other words, the talkers want little music, no music, or low volume music, while the dancers want much higher volume music.) Consider for example, a wedding reception or college reunion with a dance band.
In this context, bad acoustics means that when the music is playing, people sitting at tables throughout the tent (even far from the musicians) have extreme difficulty hearing conversation at their table.
The temporary and generally short-term nature of the structure exacerbates the problem for a number of reasons. The structure must be economical and practical for many different types of events, some with music and some without, so that high-cost or specialized acoustic treatments are prohibitive. In addition, the structure must be economical and practical for different uses of the space within the tent, such that for some events musicians are placed in one part of the tent (for example, a corner of the tent) and for some other events the musicians are placed in another part of the tent (for example, the middle of a side of the tent). This makes built-in acoustic baffling impractical. At the same time, because the structure is temporary and usually short term (often only for one day or a weekend), creating special acoustic fabrics for the event, or employing elaborate and time-consuming acoustic tuning of the space by specialists is impractical. In other words, although the part of the tent requiring acoustic isolation will vary from event to event, the acoustic treatment must also be simple to install by people who are not acoustic engineers or technicians.
The invention described herein solves this problem by acoustically isolating a portion of the tent without visually isolating that portion from the rest of the tent, and without creating physical barriers to trip people or impede crowd flow within the tent.
These large tents have been used for events such as wedding ceremonies or musical concerts, where most people in attendance are listening somewhat quietly and attentively to a relatively few celebrants or entertainers. Microphones, amplification, and audio speakers are deployed so that everyone throughout the tent will be able to hear the few people speaking or making music (the “performers”).
Just as importantly, these tents are often used for events such as cocktail receptions, where there are no performers. Attendees may be standing up, talking to the person next to them. Alternatively, attendees may be sitting at tables, talking to the people at the table.
One problem is that at some events, for a part of the event everyone wants to hear the performers, while for another part of the event only some people want to hear the performers.
An example is a wedding held under such a tent, which consists of first a ceremony and then a reception. At the ceremony the guests are focused on the bride, groom, and officiant. At the reception with dance band, some want to dance, and others want to talk to each other. This makes it harder to position loud speakers and amplification systems to perform both tasks.
Just as importantly, percussive instruments such as drums cannot be effectively controlled by the sound technician in charge of amplification or mixing. This is because drums can fill the tent with loud volume sound even without amplification. In contrast, many amplified instruments such as an electric guitar, will make little or no sound without amplification. Importantly, the acoustics within one of these tents are sufficiently different from other common venues which such musicians often play. A musician playing drums in a large tent does not get accurate aural feedback to judge how loud he or she is playing in relation to the rest of the instruments, so will tend to play louder and louder. If the sound technician simply balances the amplified instruments (e.g. voice, guitar, wind instruments) with the percussive ones, the mixed sound (amplified and not amplified) will get louder and louder until it is too loud.
It also has to be noted, that these tents are acoustically “live”, with sound bouncing off the tent roof (and tent sidewalls when in place) so that in a tent filled with people, even without music, it is often hard to hear people across a dinner table, or standing nearby.
Currently available acoustic barriers include acoustically designed wall-like partitions. These may be floor to ceiling or of varying heights. They may be solid, or somewhat transparent. They create acoustic separation by dividing the tent into separate acoustic spaces.
But they also separate the tent into distinct and separate social spaces, defeating one of the purposes of such get-togethers and impeding crowd flow under the tent. Also available are individual vertical acoustic baffles that could potentially be hung like banners from the tent roof structure, per the design of an acoustical engineer.
Canopies have been suspended to acoustically treat and condition permanent spaces, but are specially designed for each permanent space. These canopies may be of fabric or solid construction, but are often “tuned” for the space before, during and after construction, so that installation of the canopy from start to finish takes days, weeks, or months. Something that is not practical for a temporary structure for a short term event.
Note that tuning may involve fine adjustments to the placement or angling of the canopy, with acoustic testing after each adjustment. Tuning may involve adding or subtracting portions of the canopy or canopies, again with testing. Tuning may involve switching or treating the canopy material—fabric or otherwise. Tuning may involve design and manufacture of special fabrics to accomplish the particular acoustic treatment desired.
Just as importantly, these canopies are employed in concert venues, for performances. All of the attendees at the venue are listening to the performers. The canopies and other acoustic treatments may be used to condition sound by reflecting, absorbing, or transmitting it. The canopies and other acoustic treatments may be used to reflect some conditioned sound back to the performers, so that they can use the feedback to enhance their performance. However, the primary object of acoustic treatments at these venues, including canopies, is to make sure that everyone at the venue can hear the performance. For this reason, the canopies are often near the roof of the structure. But in any event, these canopies are not close to the performers, because that would contain or isolate the sound and prevent members of the audience from hearing the performance. As concert venues, they are not designed with a designated dance floor for the audience to dance.